Semiconductor light-emitting element

ABSTRACT

A semiconductor light-emitting element includes: an ohmic electrode layer formed on a surface of a semiconductor structure layer including a light-emitting layer; a reflective metal layer containing Ag formed so as to cover at least ends of the ohmic electrode layer; and a covering electrode layer formed so as to bury the reflective metal layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor light-emitting elementsuch as a light-emitting diode (LED).

2. Background Art

A semiconductor light-emitting element such as a light-emitting diode ismanufactured typically by growing an n-type semiconductor layer, alight-emitting layer, and a p-type semiconductor layer on a growthsubstrate and forming an n-electrode and a p-electrode for applying avoltage to the n-type semiconductor layer and the p-type semiconductorlayer, respectively.

As a semiconductor light-emitting element for improving its lightextraction efficiency in the above-described structure, a semiconductorlight-emitting element having a structure in which a reflective metallayer made of a highly-reflective metal is formed on the p-typesemiconductor layer and the p-electrode is formed on the reflectivemetal layer is currently known.

Japanese Patent Application Laid-Open No. 2006-41403 discloses asemiconductor light-emitting element having a structure in which ap-electrode made of a metal layer including an Ag layer is formed on ap-type semiconductor layer and an insulating protection film is formedso as to surround the p-electrode. Japanese Patent Application Laid-OpenNo. 2007-27539 discloses a semiconductor light-emitting element having astructure in which a contact layer and a reflective electrode arelayered on a p-type semiconductor layer in order and a p-electrode isprovided so as to cover the reflective electrode.

SUMMARY OF THE INVENTION

As described above, if the light-reflecting metal is formed on thep-type semiconductor layer, for example, light from the light-emittinglayer can be extracted efficiently from a surface of the n-typesemiconductor layer, for example. An example of the reflective metallayer may be made of Ag, which is a metal having a high lightreflectivity, or an alloy containing Ag. However, Ag is known for itseasy migration to another layer. Such Ag migration results in asignificant adverse effect on the reliability of the element such asdegradation in electric properties in the element.

The present invention has been made in view of the above circumstancesand an object thereof is to provide a semiconductor light-emittingelement capable of preventing migration and thereby achieving highreliability as well as having high light extraction efficiency.

A semiconductor light-emitting element according to the presentinvention includes: an ohmic electrode layer formed on a surface of asemiconductor structure layer including a light-emitting layer; areflective metal layer containing Ag formed so as to cover at least endsof the ohmic electrode layer; and a covering electrode layer formed soas to bury the reflective metal layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are cross-sectional views illustrating a structure of asemiconductor light-emitting element according to a first embodiment;

FIG. 2 is a diagram for explaining a problem to be solved by the presentinvention;

FIGS. 3A and 3B are views illustrating a structure of a semiconductorlight-emitting element according to a second embodiment; and

FIGS. 4A to 4C are cross-sectional views illustrating a manufacturingprocess of the semiconductor light-emitting element according to thesecond embodiment.

DETAILED DESCRIPTION OF THE INVENTION

A semiconductor light-emitting element according to the presentinvention has a structure in which a reflective metal layer containingAg is reliably covered by a conductive oxide film. Preferred embodimentsof the present invention will be described below in detail. Note thatsubstantially the same or equivalent elements will be denoted by thesame reference numeral in the following description and the accompanyingdrawings.

First Embodiment

FIG. 1A is a cross-sectional view illustrating a structure of asemiconductor light-emitting element 10 according to the firstembodiment of the present invention. FIG. 1B is a partially-enlargedcross-sectional view illustrating a portion of FIG. 1A in an enlargedmanner. As shown in FIG. 1A, the semiconductor light-emitting element 10has a semiconductor structure layer 11 including a light-emitting layer13. The semiconductor structure layer 11 has a structure in which ann-type semiconductor layer (first semiconductor layer) 12 having acomposition of Al_(x)In_(y)Ga_(1-x-y)N (0≦x≦1 and 0≦y≦1), thelight-emitting layer 13, and a p-type semiconductor layer (secondsemiconductor layer) 14 are grown on a growth substrate 21 in order. Thesemiconductor structure layer 11 has a structure in which the n-typesemiconductor layer 12 and the p-type semiconductor layer 14 having aconductivity type opposite to the n-type are provided so as to interposethe light-emitting layer 13 therebetween.

An ohmic electrode layer 15 is formed as a p-electrode on the p-typesemiconductor layer 14. The ohmic electrode layer 15 is made of an oxidefilm having light-transmitting and conductive properties. Examples ofthe material of the ohmic electrode layer 15 may include ITO, IZO, ZnO,etc. A reflective metal layer 16 is formed on the ohmic electrode layer15 so as to cover the entire ohmic electrode layer 15. The reflectivemetal layer 16 is made of an Ag layer, a layer made of an alloycontaining Ag, or a metal layer having a multi-layered structureincluding these layers.

A covering electrode layer 17 for burying the reflective metal layer 16is provided on the reflective metal layer 16. The covering electrodelayer 17 includes: a first covering electrode layer 17A provided so asto bury the reflective metal layer 16; and a second covering electrodelayer 17B provided so as to cover the first covering electrode layer17A. The first covering electrode layer 17A and the second coveringelectrode layer 17B each are made of a conductive oxide film. Examplesof the material of the first covering electrode layer 17A and the secondcovering electrode layer 17B may include ITO, IZO, ZnO, etc. Moreover,the first covering electrode layer 17A has an oxygen concentrationsmaller than that of the second covering electrode layer 17B.

An insulating layer 18 is provided on the covering electrode layer 17 soas to cover the covering electrode layer 17. The insulating layer 18 ismade of an insulating oxide film or nitride film, e.g., SiO₂ or SiN. Theinsulating layer 18 is provided with an aperture. In the aperture, a padelectrode 19 connected to the covering electrode layer 17 is provided.Moreover, an n-electrode 20 is provided on the n-type semiconductorlayer 12.

Referring to FIG. 2, a manufacturing-related problem to be the cause ofAg electromigration which occurs during an operation of the element willnow be described. FIG. 2 is a cross-sectional view schematicallyillustrating a case where an ohmic electrode 120 is formed on a p-typesemiconductor layer 113 and a reflective metal layer 130 containing Agis formed thereon in a semiconductor structure layer 110 comprising ann-type semiconductor layer 111, a light-emitting layer 112, and thep-type semiconductor layer 113. As an example for the prevention of Agmigration, the reflective metal layer 130 containing Ag may be coveredby an insulating layer 140 such as SiO₂, for example. Here, it ispreferable that the high-density insulating layer 140 without a filmdefect be formed in order to reliably cover Ag. A film formationtemperature of the insulating layer 140 is kept high.

The inventor of the present application focused on a fact that theformation of the insulating layer 140 at a high temperature causes Ag atan end of the reflective metal layer 130 to protrude and thereby haveirregularities in its shape. If Ag protrudes, a covering defect or crackoccurs in the insulating layer 140. Note that as the layer thickness ofthe reflective metal layer 130 containing Ag at the end thereof getssmaller, Ag is more likely to protrude. Due to the formation of theinsulating layer 140, a portion where the reflective metal layer 130 isexposed from the surface of the insulating layer 140 is formed or theinsulating layer 140 has a portion with a smaller layer thicknessespecially at the end of the reflective metal layer 130. The inventor ofthe present application attained a finding that the covering defect ofthe insulating layer 140 due to such Ag protrusion causeselectromigration and thereby leads to degradation in the reliability ofthe element.

Next, the ohmic electrode layer 15, the reflective metal layer 16, andthe covering electrode layer 17 of the semiconductor light-emittingelement 10 according to the present embodiment will be described in moredetail. Here, a case where: the ohmic electrode layer 15 is made of anITO layer; the reflective metal layer 16 is made of an Ag layer; thecovering electrode layer 17, i.e., the first and second coveringelectrode layers 17A and 17B, is made of an ITO layer; and theinsulating layer 18 is made of an SiO₂ layer.

Referring back to FIG. 1A, the covering electrode layer 17 will now bedescribed. As compared with SiO₂, ITO can be formed at a lowertemperature. Therefore, forming the covering electrode layer (ITO layer)17 on the reflective metal layer (Ag layer) 16 can reduce the risk ofcausing Ag in the reflective metal layer 16 to protrude. Thus, thereflective metal layer 16 can be reliably covered. Furthermore, evenwhen a high-temperature state is maintained during the formation of theinsulating layer (SiO₂ layer) 18, the insulating layer 18 can have aconstant layer thickness since the reflective metal layer 16 has alreadybeen covered reliably by the covering electrode layer 17. Thus, a highprotective performance and a high insulating property can be obtained.

As described above, the first covering electrode layer 17A has an oxygenconcentration smaller than that of the second covering electrode layer17B. Here, the first covering electrode layer 17A is referred to as alow-oxygen ITO layer and the second covering electrode layer 17B isreferred to as a high-oxygen ITO layer. First, the low-oxygen ITO layer17A is provided so as to bury the reflective metal layer 16. Since thelow-oxygen ITO layer 17A has a smaller oxygen concentration, thelow-oxygen ITO layer 17A has characteristics closer to a metal, therebyimproving its adhesion with the reflective metal layer 16. Note that ifthe first covering electrode layer 17A is made of ITO having a highoxygen concentration, its adhesion with the reflective metal layer 16 isreduced, thereby degrading the covering quality thereof. Furthermore, Agin the reflective metal layer 16 is easily influenced by moisture oroxygen, resulting in the generation of silver hydroxide as a result of achemical reaction. This silver hydroxide is unstable and easily turnedinto silver oxide to deposit Ag ions. This is the cause of theoccurrence of the Ag migration. Thus, the generation of silver hydroxidecan be suppressed by reducing the oxygen concentration in the firstcovering electrode layer 17A.

Furthermore, the high-oxygen ITO layer 17B formed so as to cover thelow-oxygen ITO layer 17A has a higher oxygen concentration. Thus, anaffinity with the insulating layer 18, which is also an oxide film, isenhanced, thereby making it possible to improve the adhesion between thehigh-oxygen ITO layer 17B and the insulating layer 18.

Next, with reference to FIG. 1B, the ohmic electrode layer 15 and thereflective metal layer 16 will be described. FIG. 1B is an enlarged viewof the portion surrounded by a broken line in FIG. 1A. The reflectivemetal layer 16 is formed so as to cover the ohmic electrode layer 15.Thus, the ends of the reflective metal layer 16 are in contact with thep-type semiconductor layer 14. The adhesion between the reflective metallayer 16 and the p-type semiconductor layer 14 is stronger than theadhesion between the reflective metal layer 16 and the ohmic electrodelayer 15. Therefore, due to the contact of the ends of the reflectivemetal layer 16 with the p-type semiconductor layer 14, the ends of thereflective metal layer 16 have a greater adhesion level than the otherportions of the reflective metal layer 16 in contact with the ohmicelectrode layer 15. Consequently, it is possible to prevent Ag frombeing protruded at the end of the reflective metal layer 16 by asubsequent thermal process or the like. Moreover, even if the end of thereflective metal layer 16 has a smaller thickness, the Ag protrusion canbe suppressed.

As described above, the reflective metal layer 16 containing Ag isreliably covered by the ohmic electrode layer 15 and the coveringelectrode layer 17. Therefore, the semiconductor light-emitting elementcapable of preventing the occurrence of the Ag migration and having highreliability can be provided.

While the case where the covering electrode layer 17 is formed by thetwo layers of the low-oxygen ITO layer 17A and the high-oxygen ITO layer17B has been described above, the covering electrode layer 17 may beformed such that the oxygen concentration thereof increases from thereflective metal layer 16 toward the insulating layer 18. For example,the covering electrode layer 17 can be manufactured by changingconditions for forming ITO, e.g., a formation temperature or an oxygenconcentration to be supplied. It is only necessary that the ITO layerhaving a low oxygen concentration is formed in contact with thereflective metal layer 16 and the ITO layer having a high oxygenconcentration is formed in contact with the insulating layer 18. Forexample, the covering electrode layer 17 may be formed by three or moreITO layers.

While the case where the reflective metal layer 16 is formed so as tocover the entire ohmic electrode layer 15 has been described above, itis only necessary that the reflective metal layer 16 is formed so as tocover at least the ends of the ohmic electrode layer 15. In other words,the ohmic electrode layer 15 may have a portion not covered by thereflective metal layer 16. Due to the covering of the ends of the ohmicelectrode layer 15 by the reflective metal layer 16, a portion where thereflective metal layer 16 is in contact with the p-type semiconductorlayer 14 is formed, thereby obtaining enhanced adhesion.

Note that the ohmic electrode layer 15 and the reflective metal layer 16function as a light-reflecting layer. This light-reflecting layerreflects light emitted from the light-emitting layer 13 with highefficiency, thereby making it possible to extract a lot of light from alight extraction surface.

Note that the covering electrode layer 17 preferably has a sheetresistance lower than that of the ohmic electrode layer 15. If thecovering electrode layer 17 has a lower sheet resistance, current isdiffused in the covering electrode layer 17, thereby making it possibleto homogenize the distribution of current supplied to the p-typesemiconductor layer 14.

Moreover, the covering electrode layer 17 and the ohmic electrode layer15 both form ohmic contact with the p-type semiconductor layer 14. Thus,current can be supplied to the p-type semiconductor layer 14 not onlyfrom the region where the ohmic electrode layer 15 is formed but alsofrom the region of the covering electrode layer 17 in contact with thep-type semiconductor layer 14, thereby increasing the light-emittingregion. Moreover, as viewed from the p-type semiconductor layer 14 side,the reflective metal layer 16 is interposed between the coveringelectrode layer 17 and the ohmic electrode layer 15. Thus, the rimportion of the light-emitting region formed by the reflective metallayer 16 becomes less visible due to the existence of the coveringelectrode layer 17 and the ohmic electrode layer 15, therebyhomogenizing the in-plane emission intensity. Therefore, a high luminousefficiency and light emission uniformity can be achieved.

Second Embodiment

FIGS. 3A and 3B are a cross-sectional view and a plan view,respectively, illustrating a structure of a semiconductor light-emittingelement 30 according to the second embodiment. More specifically, FIG.3A is a cross-sectional view taken along the line V-V in FIG. 3B. Asshown in FIG. 3A, the semiconductor light-emitting element 30 has thesame structure as the semiconductor light-emitting element 10 of thefirst embodiment in that the ohmic electrode layer 15 as thep-electrode, the reflective metal layer 16, the covering electrode layer17, and the insulating layer 18 are formed on the p-type semiconductorlayer 14 of the semiconductor structure layer 11. The semiconductorlight-emitting element 30 of the present embodiment has an n-electrode35 formed in a through hole VA extending from the p-type semiconductorlayer 14 side into the n-type semiconductor layer 12 through the p-typesemiconductor layer 14 and the light-emitting layer 13 and connected tothe n-type semiconductor layer 12. Moreover, the semiconductorlight-emitting element 30 includes a p-side wiring 34A connected to thecovering electrode layer 17 and an n-side wiring 34B connected to then-electrode 35.

More specifically, an insulating protection film 36 is formed on theinsulating layer 18 so as to cover the insulating layer 18. In a part ofthe semiconductor structure layer 11, the through hole (via) VA isprovided so as to extend from the p-type semiconductor layer 14 sideinto the n-type semiconductor layer 12 through the p-type semiconductorlayer 14 and the light-emitting layer 13. An inner surface of thethrough hole VA in the semiconductor structure layer 11 is covered bythe insulating protection film 36. The through hole VA is provided withan aperture. The n-electrode 35 is provided in that aperture, therebyforming an n-side contact portion NC. Specifically, the n-electrode 35is provided in the through hole VA, runs through the insulatingprotection film 36, and is connected to the n-type semiconductor layer12. Moreover, the n-side wiring 34B is provided on the insulatingprotection film 36 and connected to the n-electrode 35 in the n-sidecontact portion NC. The p-side wiring 34A is provided on the insulatingprotection film 36, runs through the insulating protection film 36 andthe insulating layer 18, and is connected to the covering electrodelayer 17 in a p-side contact portion PC. Note that FIG. 3B is a top viewof the semiconductor light-emitting element 30. For the ease ofunderstanding, the p-side contact portion PC and the n-side contactportion NC are indicated by broken lines.

As shown in FIG. 3A, the semiconductor light-emitting element 30 issupported by a support substrate 31. A support substrate-side insulatinglayer 32 is provided on the surface of the support substrate 31. Ajoining layer 33 is provided on the surface of the supportsubstrate-side insulating layer 32. The joining layer 33 includes ap-side joining layer 33A connected to the p-side wiring 34A and ann-side joining layer 33B connected to the n-side wiring 34B. These twojoining layers 33A and 33B are insulated from each other by the supportsubstrate-side insulating layer 32. Note that the insulating layer 18 issometimes referred to as a semiconductor layer-side insulating layer inthe present embodiment.

Examples of the material of the support substrate 31 may includeconductive materials such as Si and SiC. A material such as AuSn, forexample, can be used as the material of the p-side joining layer 33A andthe n-side joining layer 33B. Examples of the material of the insulatingprotection film 36 and the support substrate-side insulating layer 32may include insulating materials such as SiO₂ and SiN. A metal such asTi, Al, Pt, or Au, for example, can be used as the material of then-electrode 35. Examples of the material of the p-side wiring 34A andthe n-side wiring 34B may include metals such as Ti, Pt, and Au.

Next, with reference to FIGS. 4A to 4C, a method for manufacturing thesemiconductor light-emitting element 30 will be described. First, asshown in FIG. 4A, the n-type semiconductor layer 12, the light-emittinglayer 13, and the p-type semiconductor layer 14 are grown on a growthsubstrate 39 in order. In the present embodiment, a sapphire substratewith a crystal growth plane being a c-plane was used as the growthsubstrate 39. Moreover, a metal organic chemical vapor deposition method(MOCVD method) was employed for the growth of the semiconductorstructure layer 11. Subsequently, the ohmic electrode layer 15 wasformed on the p-type semiconductor layer 14. The reflective metal layer16 was formed so as to cover the ohmic electrode layer 15. The coveringelectrode layer 17 was formed so as to bury the reflective metal layer16. When forming the ohmic electrode layer 15, the reflective metallayer 16, and the covering electrode layer 17, a sputtering method wasemployed. When forming the reflective metal layer 16, a lift-off methodwas employed. Specifically, the shape of the ohmic electrode layer 15was first patterned on the surface of the p-type semiconductor layer 14by photolithography and then the ohmic electrode layer 15 was formed.Similarly by means of the patterning by photolithography and filmformation by the sputtering method, the reflective metal layer 16 andthe covering electrode layer 17 were formed. At this time, the surfaceof part of the p-type semiconductor layer 14 was exposed. Subsequently,the insulating layer (semiconductor layer-side insulating layer) 18 wasformed so as to cover the exposed surface of the p-type semiconductorlayer 14 and the covering electrode layer 17. When forming theinsulating layer 18, the sputtering method was employed.

Next, as shown in FIG. 4B, a resist having an aperture is formed by thephotolithography method in a region where the insulating layer 18 isdirectly formed on the p-type semiconductor layer 14 and etching wasperformed in that region. Consequently, the through hole VA extendingfrom the p-type semiconductor layer 14 side into the n-typesemiconductor layer 12 through the p-type semiconductor layer 14 and thelight-emitting layer 13 was obtained. Subsequently, the insulatingprotection film 36 was formed on the whole of the inner surface of thethrough hole VA and the surface of the insulating layer 18. When formingthe insulating protection film 36, the sputtering method was employed.Next, the insulating protection film 36 was removed in part of thethrough hole VA by etching. The n-electrode 35 was formed on the surfaceof the exposed n-type semiconductor layer 12. Subsequently, etching wasperformed on the insulating layer 18 and the insulating protection film36 to form an aperture AP extending up to the covering electrode layer17 through the insulating protection film 36 and the insulating layer18. Thereafter, the p-side wiring 34A and the n-side wiring 34Bconnected to the covering electrode layer 17 and the n-electrode 35,respectively, were formed on the insulating protection film 36. Whenforming the p-side wiring 34A and the n-side wiring 34B, the sputteringmethod was employed. Note that the aperture AP may be formed so as torun through the covering electrode layer 17 to have a depth extendedinto the reflective metal layer 16. In such a case, the p-side wiring34A is directly in contact with the reflective metal layer 16.

Subsequently, as shown in FIG. 4C, after the support substrate 31 wasprepared and the support substrate-side insulating layer 32 was formedon the support substrate 31, the p-side joining layer 33A and the n-sidejoining layer 33B were formed. Thereafter, the semiconductor structurelayer 11 was joined with the support substrate 31 via the p-side wiring34A and the p-side joining layer 33A, and the n-side wiring 34B and then-side joining layer 33B. This joining was made by thermocompression.Subsequently, the support substrate 31 was subjected to a polishingprocess to be thinned and the growth substrate 39 was removed by a laserlift-off technique. Thereafter, etching was performed on the exposedsurface of the n-type semiconductor layer 12 so as to form aconcavo-convex structure. Then, the support substrate was divided bydicing or the like to obtain the semiconductor light-emitting element30.

In the present embodiment, the semiconductor structure layer 11 has thethrough hole (via) and the covering electrode layer 17 and then-electrode 35 are formed on the same surface side of the semiconductorstructure layer 11, i.e., the p-type semiconductor layer 14 side. When asemiconductor light-emitting element has such a via structure, themigration of Ag used as the material of the reflective metal layer 16becomes especially problematic. Specifically, in view of its reflectionefficiency, i.e., its light extraction efficiency, it is preferable thatthe reflective metal layer 16 be formed as wide as possible. On theother hand, the reflective metal layer 16 may be structurally very closeto the n-electrode 35 and the n-side wiring 34B connected to then-electrode 35. Specifically, when the element is seen from the above,the reflective metal layer 16 and the n-side wiring 34B may be formed inan overlapping manner. Therefore, it is required that the reflectivemetal layer 16 is reliably covered, i.e., the reflective metal layer 16is reliably insulated from the n-electrode 35 and the n-side wiring 34B.

The characteristic of the present invention capable of reliably coveringthe reflective metal layer 16 containing Ag is especially effective inthe present embodiment. More specifically, in the light-emitting elementhaving the structure as in the present embodiment in which both of then-side electrode and the p-side electrode are formed on the same surfaceside, the number of defectives can be dramatically reduced as comparedwith the conventional techniques. Moreover, this makes it possible toform the light reflection region more widely, thereby improving thelight extraction efficiency. Therefore, the semiconductor light-emittingelement having high reliability and improved light extraction efficiencycan be provided.

As described above, according to the present invention, the ohmicelectrode layer is formed on the semiconductor structure layer, thereflective metal layer is formed so as to cover at least the ends of theohmic electrode layer, and the covering electrode layer is formed so asto bury the reflective metal layer. Thus, the migration of Ag containedin the reflective metal layer can be suppressed and the semiconductorlight-emitting element with high reliability can be therefore provided.

While the case where the first semiconductor layer and the secondsemiconductor layer are an n-type semiconductor layer and a p-typesemiconductor layer, respectively, has been described in theaforementioned embodiments, conductivity types of the first and secondsemiconductor layers are not limited thereto. The first and secondsemiconductor layers may have conductivity types opposite to those inthe aforementioned embodiments.

This application is based on a Japanese Patent application No.2013-196723 which is hereby incorporated by reference.

What is claimed is:
 1. A semiconductor light-emitting elementcomprising: an ohmic electrode layer formed on a surface of asemiconductor structure layer including a light-emitting layer; areflective metal layer containing Ag formed so as to cover at least endsof the ohmic electrode layer; and a covering electrode layer formed soas to bury the reflective metal layer, wherein the covering electrodelayer is made of an oxide film having a conductive property, and whereinthe ohmic electrode layer is made of an oxide film havinglight-transmitting and conductive properties.
 2. The semiconductorlight-emitting element according to claim 1, wherein the coveringelectrode layer includes a first covering electrode layer formed so asto bury the reflective metal layer and a second covering electrode layerformed so as to cover the first covering electrode layer, and wherein anoxygen concentration of the first covering electrode layer is smallerthan an oxygen concentration of the second covering electrode layer. 3.The semiconductor light-emitting element according to claim 1, furthercomprising an insulating layer formed so as to cover the coveringelectrode layer.
 4. A semiconductor light-emitting element comprising:an ohmic electrode layer formed on a surface of a semiconductorstructure layer including a light-emitting layer; a reflective metallayer containing Ag formed so as to cover at least ends of the ohmicelectrode layer; a covering electrode layer formed so as to bury thereflective metal layer; and an insulating layer formed so as to coverthe covering electrode layer; wherein the semiconductor structure layerhas a structure in which a p-type semiconductor layer and an n-typesemiconductor layer are provided so as to interpose the light-emittinglayer therebetween, and a surface of the semiconductor structure layeris a surface of the p-type semiconductor layer, and wherein thesemiconductor light-emitting element further comprises: an insulatingprotection film formed so as to cover the insulating layer and an innersurface of a through hole extending from the p-type semiconductor layerside into the n-type semiconductor layer through the p-typesemiconductor layer and the light-emitting layer; an n-electrodeprovided in the through hole and connected to the n-type semiconductorlayer through the insulating protection film; a p-side wiring connectedto the covering electrode layer through the insulating protection film;and an n-side wiring connected to the n-electrode.
 5. A semiconductorlight-emitting element comprising: an ohmic electrode layer formed on asurface of a semiconductor structure layer including a light-emittinglayer; a reflective metal layer containing Ag formed so as to cover atleast ends of the ohmic electrode layer; and a covering electrode layerformed so as to bury the reflective metal layer; wherein each of theohmic electrode layer and the covering electrode layer is made of an ITOlayer.
 6. The semiconductor light-emitting element according to claim 1,wherein a sheet resistance of the covering electrode layer is smallerthan a sheet resistance of the ohmic electrode layer.